System of motor control.



L JANISOH & W. LINKE. SYSTEM OF MOTOR CONTROL. APPLICATION FILED MAY 7, 1909.

1,003,464, Patented Sept. 19, 1911.

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UNITED STATES PATENT orriou.

LEQPQLD JANISGH AND WILLY LINKE, DIE BERLIN, GERMANY, A$ IGNQRSL TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.,

SYSTEM 01? MOTOR CONTROL,

Sept. 19, 1911.

p'plication filed May 7, 1908. SerialNo. 494,578.

To all whom it may concern:

Be it known that we, LEOPOLD JANIS H and WILLY LiNKn, subjects of the Emperor of Germany, residing at Berlin, Germany, have invented certain new and useful Improvements in Systems of Motor Control, of which the following is a specification.

Our invention relates to systems of motor control and more particularly to such a system in whicithe motor, when the load becomes excessive, will remain stationary without being injured, and will automatically start up again when the load is de-' creased. Such a system is particularly advantageous when the motor drives an anchor Windlass, or the like.

Our invention consists in the combination with a motor, of a generator supplying current thereto, and means driven by the motor for automatically weakening the field of said generator upon a decrease in speed of said motor.

' Other features of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of our invention, however, reference may be had to the following description taken in connection withthe accompanying drawing, in which Figurev 1 is a diagrammatical representation of a control system in accordance with our invention; and Fig. 2 shows a modifica tion of our system.

In the figures of the drawing, A is the armature of a generator having a separately-excited field winding a, and a commutating field winding 9.

B is the armature and b is the series field winding of a motor connected to the arms.- ture of the generator through a switch C.

D represents the armature of a separate exciter which we have chosen to illustrate as being direct connected to the armature B of the motor, but which may be mechanically driven by the motor in any suitable manner. The'field winding (Z of the ex citer is se arately-excited from the lines Z and Z and is arranged to receive a constant excitation. y

The operation of our system is as follows: Upon the ,closin of the switch C, sufiicientcurrent is en pied the motor to start it, due to the residual magnetism of the generator field. As the motor starts, the exciter of the generator in a direction opposite to armature D generates voltage because of its revolution andsupplies current to the field winding or or" the generator. As the motor speeds up, the voltage of the 'exciter increases'and strengthens the field oi the generator, until it is saturated. Thus the speed of the motor is increased to a certain value dependent upon the saturation of the field of the generator. If a load is put on the motor, which slows it down, the current supplied the iield winding a of the generator is decreased, and it this load is excessive and persists for any length of time, the motor will come to rest, because the voltage generated by the generator armature A is dependent upon the current fiowing through the field winding as, which in turn is dependent upon the speed of the motor armature B. It will, therefore, be seen that when the s cool of the motor falls, the voltage supp ied it falls in such a manner that the amount of current supplied bythe generator never exceeds a certain value, and the motor when at rest will. not receive enough current to injure it.

If the current of the generator, when the motor armature B is stationary, is not sulficient to start the motor, suflicient current may be obtained by shifting the brushes that of the rotation of the generator. In ordinary machines the amount that the brushes may be shifted, is limited by the sparking at the brushes. We, therefore, preferably em loy a generator havin commutating fiel poles having a win ing 9 thereon. The short circuited current or such generators may be easily regulated by the position of the brushes.-

We may also, in control systems built'in accordance with our invention, supply the generator with a relatively small field winding which is constantly excited. Fi 2 shows such a system in which the win ing it is constantly excited from the lines Z and Z This winding 12. supplies just enough excitation to cause sufficient current to flow to just start-the motor.

Although we have shown the field windings of the machines connected in a articular manner, it is obvious to those sk1lled in the art that other connections may be employed to obtain the same results, and we aim in the claims, hereto appended, to cover all modifications of our system that do not involve a departure from the spirit crease in the speed of said motor whereby upon the occurrence of an overload on said motor it is slowed down.

2. In combination, a motor, a separatelyeXcited generator supplying current thereto, and means for automatically weakening the field of said generator upon a decrease in the speed of said motor whereby upon the occurrence of an overload on said motor it is slowed down.

3. In combination, a motor, a generator having a separately-excited field winding supplying current to said motor, and an exciter mechanically driven by said motor and supplying current to the field winding of said generator.

4. In combination, a motor, an exciter mechanically driven thereby, and a generator having two separately-excited field windings, one of said windings being relatively small and constantly excited and the other being supplied with current by said exciter.

5. In combination, a motor, a generator supplying current thereto and having a separately-excited field winding, and a separately-excited exciter mechanically driven by said motor and su plying current to the separately-excited field winding of said generator.

6. In combination, a motor having a series field winding, a generator supplying current thereto, and means driven by said motor for automatically weakening the fieldof said generator upon a decrease in the speed of said motor.

7 In combination, a motor having a series field winding, a separately-excited generator supplying current thereto, and means for automatically weakening the field of said generator upon a decrease in the speed of said motor.

8. In combination, a motor having a series field winding, a generator having a separately-excited field winding supplying current to said motor, and an exciter mechanically driven by said motor and supplying current to the field winding of said generator.

9. In combination, a motor having a series field windin an exciter mechanically driven thereby, an a generator having two separately-excited field windings, one of said windings being relativel small and constantly excited and the ot er being supplied with current by said exciter.

10. In combination, a motor having a series field winding, a generator supplying current thereto and having a separately excited field winding, and a separately-excited exciter mechanically driven by said motor and supplying current to the separately-excited field winding of said generator.

In witness whereof; we have hereunto set our hands this 17th day of April, 1909.

LEOPOLD J ANISCH. WILLY LINKE. Witnesses:

RICHARD NEUMANN, LIONEL FLEISCHMANN. 

